SYMPTOM:
When a positioner is wired to RC2800PRKX2SUMC, the positioner runs just for a second and then stops.
And
‘
E will appear in the mode column of the display. To reset, hit either mode key.
Why does this happen? Most commonly, The microprocessor will not let the motor run more than a second if the
micro
’
sees no pulses coming in from the reed switch in the positioner. If the positioner moves slightly, it means
your motor and motor wires are probably OK.
POSSIBLE CAUSES:
This usually means that the control unit is not getting pulses back from the positioner. First remove the pulse
wires from terminal #10 and #11 from the back of the control unit. Using a digital volt meter or equivalent,
measure the voltage that is present between terminal #10 and #11 for about 1 second when you command the
unit to go. You should have 11.3 VDC. If this voltage does not appear briefly, turn off the control unit and
measure the resistance between terminal #10 and #11. If the resistance is less than 5000 Ohms, it means the
protective MOV across terminal #10 and #11 inside the control unit is leaky or shorted. If the MOV is damaged it
means it took a voltage spike over about 25 volts. It failed but protected the internal circuitry. Unplug the control
unit, remove the cover, and using diagonal cutters, cut one lead of the red MOV on the rear pc board terminal
#10 and #11.
Now turn on the control unit and check for the 11.3 VDC between terminals #10 and #11. If the voltage is
present, turn off the control unit, replace the cover and reattach the wires to terminal #10 and #11. Turn on the
control unit and press CCW or CW to see if the positioner now operates properly. If so, use the
“
Auto Cal
”
feature
and recalibrate the unit as described at the beginning of this manual. Call M2 and order a new MOV. The system
can be operated without the MOV, but during this time you have no voltage spike protection. When all else fails,
call M2 at 559 432 8873 and we will help you trouble shoot the system.
If the above appears OK, then the missing pulses maybe caused by a control cable problem or a
damaged Positioner.
Again, turn off the control unit and remove the wires from terminal #10 and #11. Attach
your meter in the resistance mode across the two leads just removed. Two states can exist. Your reading will
either be a total open 10 meg Ohms or more OR a total short measuring only the resistance of the wires running
to the positioner. Now with the meter leads still connected and measuring Ohms, turn on the control unit and
press CCW or CW and make the rotator move. Watch the meter to see the state of the reed switch changes.
Each motor revolution will open and close the reed switch twice so you should see the meter change from open
to shorted. This may take a few tries as the reed switch is open normally about 60% of the time. If you see no
change of state, you either are not on the reed wires, or there is a
break in the wires between the positioner and
the control unit or you have a faulty reed switch. The second of the two is very unlikely.
Most of the time this
problem is due to a wiring or connection problem somewhere between the positioner and the control
unit.
Use common sense trouble shooting your wiring.
SYMPTOM:
Positioner operates, but readout is erratic or consistently reads higher or lower than where the antenna
system is actually pointing.
POSSIBLE CAUSES:
This is also an indication of a wiring problem. Long runs of cable that have a cut in the jacket can fill with water
and significantly increase the inter
-
wire capacity. This can allow motor spikes to be picked up by the pulse (reed
switch lines) and add extra pulses to the count. It can also cause such distortion of the square wave from the
reed switch, that the microprocessor can
’
t read the actual pulse count. Replace the cable or run a separate
RG
-
58U or equivalent line for the reed switch. This is not usually an indication that the reed switch itself is faulty.
Don
’
t remove the positioner until you are absolutely sure the problem is in the positioner.
TROUBLE SHOOTING
